The furnace has a usable zone of 12” diameter x 22” high (305 mm x 559 mm), this design is ideal for high volume large batch processing.

This furnace features five chambers, a bottom indexing chamber containing a transfer mechanism, a chamber for loading and unloading, a heating chamber, one for cooling and lastly one for controlled oxidation. During normal operation, all chambers are isolated from one another.

A hydraulic lift and motorized indexing mechanism move the load stacks from one station to the next. Depending on process parameters, this furnace produces a sintered load every 45 minutes.

The hot zone is capable of temperatures up to 2100°C and is manufactured with tantalum or tungsten.

Furnace Chambers

Load/Unload Chamber

Specific process information for new work stacks can be bar-coded at any point in the PC and will be buffered until the new run is initiated. The loading cycle will prepare the atmosphere before being transferred to the sintering chamber. When a load is complete, it can be removed from the (un)loading chamber at any time during operation. This chamber has it’s own vacuum pump and valve for atmosphere preparation prior to the heat cycle.

Hot Zone Chamber

The heart of the furnace, this zone with excellent uniformity (+/- 10 °C), can be made out of Tungsten, Tantalum, or Molybdenum. Heating elements and shields can be fabricated with different sheet thicknesses, rigidized and grain-stabilized materials to maximize life expectancy. The hot zone in this particular furnace can accommodate a work stack that is up to 8″ in diameter and 16″ high.

The hot zone chamber is isolated from the other chambers and connects to the high vacuum pumping system. The pumping system removes volatiles and byproducts from the arts as they are heated.

Rapid Cooling Chamber

Equipped with a high power heat exchanger, this chamber allows a newly sintered load of 100 Lbs. to be cooled to ambient in less than 30 minutes with entry temperatures above 1000°C. A unique infra-red temperature sensor ensures accurate readings and measures load temperature rather than the surrounding cooling gas temperatures.

Controlled Oxidation Chamber

A technique ensuring quality work parts by controlling the oxidation process that would otherwise take place in an uncontrolled manner after unloading. As any other chamber, it’s environment is sealed from the other chambers except during load transfer.

Work Transfer Chamber

The work-transfer chamber is located directly beneath the four chambers described above. It contains the mechanism for raising, lowering and moving the work stacks in transit from station to station. A chamber door is provided to give access to the furnace chamber for maintenance. Two windows are provided for observation. This chamber ensures an oxidation free environment for maximum hot zone life and inert work transfer conditions.

All furnace chambers are fabricated of stainless steel, Heli-arc welded, vacuum tight, polished and double-walled (water-jacketed) where needed. All “O” ring seals are of Viton. The system is equipped with all safety interlocks and provisions to comply with NFPA codes for industrial furnaces.

Power Supply

The heater power supply is a 100 to 150 kVA (dependent on maximum temperature and ramp rate) three-phase SCR-controlled transformer package housed in the power supply & instrumentation enclosure. The transformer is sized with extra power for fast ramp rates and has two secondary voltage taps on the transformer, one for new elements and one to match to compensate for any change in resistance due to element aging. A set of water cooled Power Cables carries power from the transformer power bus to the heating elements. All protective and safety devices are incorporated, meeting all applicable NFPA standards.

A recipe contains all information needed to complete a sintering run from start to finish. For engineers or maintenance personnel, all system functions can be controlled manually and settings are available through the software interface. The HMI sports intuitive operator displays for trending, alarming, security, logging, system overviews and run status.

Batch IDs or part numbers are scanned in or entered before a run, looked up in a central database and a corresponding recipe is loaded containing all parameters to run a specific heat, cool down and controlled oxidation profile. When a run is complete, a beacon and pop-up screen will alert the operator.

Vacuum system

The High Vacuum Pumping System is capable of evacuating this furnace down to the 10-6 Torr Range and is able to handle large gas loads. The vacuum system includes the following:

An optional turbo pumping system is available to obtain a vacuum level of 10-7 Torr range.

Gas System

This furnace is designed to operate in a process gas environment at internal pressures of 2 P.S.I.G. (0.14 kg/sq. cm.) or in vacuum. All chambers are equipped with pressure switches and relief valves to monitor and control gas pressures.

The process gas system includes components to allow a controlled oxidation step for introducing an oxidizing gas to the newly sintered and cooled parts, at programmable rate.

Water Cooling System

The furnace cooling system is designed to adequately cool the various furnace components that require water cooling. Each major water circuit is provided with a flow switch and shut-off valve. If water flow is not sufficient for 5 seconds or more, an alarm activates and the corresponding components will be shut down in a safe manner.
For rapid cooling, the cooling chamber is equipped with a water-cooled gas heat exchanger.

To obtain consistent cool-down times and eliminate dependency on plant water, the furnace can also be equipped with a closed-loop chiller recirculator.